A video format signal is formulated to contain not only digitized video information and vertical and horizontal synchronization signal components but also additional signal components such as, for example, time-axis compressed sound information signal components and the control data signal components necessary for the reproduction of the video and sound information. Such a video format signal is recorded on an appropriate record medium such as a video disc and is reproduced in accordance with the control data in a "still-picture-with-sound" (SWS) system or a computerized video game machine.
The control data contained in a video format signal is predominant over various phases of the operation of the system to reproduce video and sound information in such a recording and reproducing system and is for this reason required to be completely cleared of errors before the information is reproduced. A video format signal recording and reproducing system is known which uses redundant parity check bits to correct errors in the digital control data in the video format signal received or read from a record medium. The parity check bits are formulated in association with the digital control data and are preliminarily inserted into the video format signal supplied or recorded in the medium. For correcting errors of the digital control data with the use of such parity check bits, the digital data extracted from the video format signal received or read from a record medium are once stored in the form of an n-dimensional sequence (where n is an integer) which is implemented by for, example, a three-dimensional data block. Errors contained in the digital data are thus detected and corrected with the aid of the redundant parity check bits which form part of such a data block.
In a recording and reproduction system having these features, it is desirable that the digital data such as typically the control data be inserted compactly into each of the fields (or frames) of the video format signal to make an effective use of the limited time-axis vacancies of the video format signal. It is also desirable that the timings at which the digital data are to be extracted from the video format signal and the timings at which errors of the digital data are to be corrected be streamlined to enable the system to operate efficiently in its entirety and to improve the performance efficiency of a memory used in the system. The present invention contemplates provision of a method and a system which will satisfy these demands.